Improved methoxycarbonylation process
Publication Date: 2005-Aug-30
The IP.com Prior Art Database
Mr C van Biljon: ATTORNEY [+5]
WO2004089865: PATAPP [+1]
According to the present invention a carbonylation process comprises reacting at least one unsaturated reactant in the form of a compound having an aliphatic moiety with at least one unsaturated carbon-carbon bond; carbon monoxide; and a nucleophilic co-reactant in the presence of a Group VIII metal catalyst wherein the catalyst is prepared by the combination of i) a source of Group VIII metal; ii) a ligating compound to coordinate to the Group VIII metal, which ligating compound includes at least one atom selected from phosphorus, arsenic and antimony; and iii) a composition prepared by combining a source of boron and one or more sources of R1 and R2, each of R1 and R2 being an organic group which is the same or different, which source of boron and one or more sources of R1 and R2 are capable of reacting with each other to form an anion or source thereof of general formula (II)(See full text document) wherein R1 and R2 are the same or different, and each R1 and R2 is an organic group; and the composition being characterized therein that at least one source of R1 and/or R2 is an aliphatic organic compound which includes at least one hydroxyl group and at least one carboxyl group.
USE OF AN ANION IN A CARBONYLATION PROCESS, WHICH ANION INCLUDES AN ALIPHATIC MOIETY
This invention relates to a process for the carbonylation of an unsaturated reactant in the form of a compound having an aliphatic moiety with at least one unsaturated carbon-carbon bond which comprises reacting the unsaturated reactant with carbon monoxide and a nucleophilic co-reactant in the presence of a carbonylation catalyst.
Carbonylation reactions of unsaturated compounds, such as olefinically or acetylenically unsaturated compounds are well known in the art. The carbonylation of olefins has been described in numerous European patents and patent applications, e.g. EP-A-0495548, EP-A-0227160, EP-A-0495547, EP-A-0489472, EP-A-0282142, EP-A-04489472, EP-A-0106379 and EP-A-0799180. Examples of the carbonylation of acetylenically unsaturated compounds can be found in EP-A-0499329, EP-A-0441447 and WO 9515938.
Depending on the nature of the co-reactant, the said unsaturated compounds can be converted into esters, acids, anhydrides, thio-esters, amides, etc. The carbonylation of olefins with nucleophilic compounds in the presence of a Group VIII metal catalyst has been extensively described in the textbook “New Syntheses with Carbon Monoxide”, Ed. J. Falbe (Springer-Verlag 1980). It is believed that the carbonylation reactions proceed under the influence of an active catalyst system containing one or more Group VIII metal cations, in complex coordination with an organic ligand and a suitable anion.
The appropriate organic ligand is usually selected from a mono- or bidentate ligand.
The source of anions is usually a protonic acid. Preference is in particular given to sources of non- or weakly coordinating anions. Since halide anions, in particular a chloride anion, tend to coordinate fairly strongly to palladium (Group VIII metal), the anion is preferably derived from strong acids excluding hydrohalogenic acids.
A major drawback in said carbonylation reactions is the tendency of the ligand, like organophosphines, to react with catalyst intermediates and/or reaction products and/or reagents and/or reaction diluents to form inactive phosphonium salts. For examples see R.P. Tooze et al. J. Chem. Soc.,
DaltonTrans.; (2000); 3441. The subsequent loss in catalyst activity and stability due to reduced concentrations of the stabilising ligand renders these reactions unfavorable from a commercial point of view.
A specific example of such a case is in hydroesterfication reactions (carbonylation reaction of an unsaturated reactant with an alcohol as nucleophilic co-reactant) where the acid promoter (that is the source of the anion) can react with the alcohol (most notably with methanol as the co-reagent) leading to a fraction of the acid being esterified. It is believed that the product of this side reaction can act as a potent alkylating agent which subsequently reacts with the free ligand (most notably triorganophosphin...